Water is a precious resource and one of the natural elements that needs to be conserved. Many regions in the world have scare water resources and the heavy industrial use further depletes the natural resource in developed and developing countries. In countries like Saudi Arabia it is critical to manage this resource and maximize the use.
Water such as ground water, recycled and industrial waste water; have to be treated to remove undesirable and even toxic contaminants, particularly heavy metal contaminants in order to be reusable. Ground water depending on the geographical region and other factors may contain higher amount of contaminants such as heavy metals and may not be desirable for human consumption. Many industrial processes utilize aqueous solutions of heavy metals, such as lead and copper for manufacturing of batteries and electroplating solutions. The industry used contaminated water is discarded into the environment and they in turn contaminate the surrounding soil. It may be beneficial to treat the water to remove the contaminants and reuse the water to conserve water. The industrial waste water when discarded also contaminates the soil and increases the risk of many diseases by making the soil toxic.
Unfortunately, the removal of such heavy metals from the water used in these processes has proven to be not only difficult but also expensive. Prior art processes have utilized quite expensive adsorbents, such as activated carbon, activated sludge, various types of natural clays, carbon aerogels, coirpith carbon, natural zeolites, date pits and ion exchange resins.
Prior art references elude several methods and chemicals for purification of contaminants. For example, an absorptive bed, adding chemicals, reacting with gasses, automatic feedback control system for a water treatment apparatus, such as a recirculating solids contact clarifier, and a polymer etc. These methods and chemicals are added to facilitate the formation of a sludge comprising heavy metals, gypsum and calcium carbonate by changing the pH, adjusting the pH and the temperature to precipitate the contaminants. In other methods, an acid which gels to polymerize and/or precipitate the contaminant-containing silica matrix to form an easily dry and separable solid is demonstrated. (Crawford et al. US Patent application 2009/0184054, Zadera et al. U.S. Pat. No. 4,059,513, Salem et al. U.S. Pat. No. 5,601,704, McLaughlin et al. U.S. Pat. No. 5,266,210, Zeijlstra et al. U.S. Pat. No. 4,338,200, and Grant et al. U.S. Pat. No. 5,370,827).